Developers Active in Time have gone one step further, and released a video of the first swimming app developed for the Watch. The app is capable of measuring strokes, stroke type, lengths and heart rate.

This should make it the perfect tool to track your swim, with the heart rate data allowing more accurate reporting of calorific burn.

The company has made a similar app for the Pebble smartwatch, but started with an Apple Watch app as soon as watchOS 2 was announced last month at WWDC. The updated OS allows for native apps, allowing it to work remotely, away from a smartphone.

They have shown off the app in use at the London Aquatics Centre, host of the 2012 Olympics.

The developers had to overcome several obstacles, firstly that the touch screens didn't work under water. Tim Bradley writes in a blog post, "The screen is incredibly bright and clear — possibly the best we've ever used whilst swimming.

"On the downside we initially had some buttons on the in-swim screen and found that the water was activating them. Our solution there was to hide all functions behind a force touch menu."

The biggest obstacle though? Apple itself -- the company won't allow apps "that encourage users to use an Apple Device in a way that may cause damage to the device".